For reasons of decreasing volume and weight, increasing power density, improving portability, and the like, three-dimensional (3D) semiconductor structures have been developed. In some typical manufacturing processes for 3D semiconductor structures, a stack comprising a plurality of layers may be formed on the substrate, openings then be formed through the stack, and suitable materials for forming vertical structures are provided into the openings. The openings and the vertical structures formed therein typically have high aspect ratios. This may lead to interior stress and thereby distortion and failure of the devices.